Fixed Steady for Square Stock

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Fixed Steady for Square Stock

This topic has 15 replies, 9 voices, and was last updated 22 April 2020 at 12:22 by HOWARDT.

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21 April 2020 at 22:55 #466204
woody1
Participant
@woody1
Evening,

How would you go about boring a 19mm diameter hole in a 100-115mm length 30mm square ally on a 7×12? I can only think to mount the stock, put a long drill in the 3 jaw which would be a pain, rough finish and inaccurate. The best option would be the 4 jaw and a steady. However the only way I can think to make a steady for Square is use a large bearing (which I have) cast up a housing plus an inside race with fixings either side to clamp. Am I over over thinking this? I have limited experience with square and have had some failures doing similar. Bloody shape has to many sides!

Thanks.
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21 April 2020 at 22:55 #10176
woody1
Participant
@woody1
21 April 2020 at 23:06 #466206
Hopper
Participant
@hopper
You need a cat's cradle. Basically a round sleeve that fits over your square bar where the steady sits. Eight bolts with locknuts – four around the diameter at each end– hold the sleeve in position.
21 April 2020 at 23:09 #466207
not done it yet
Participant
@notdoneityet
Don’t know, but… maybe start with a piece longer than finished size and turn, with tailstock support, a section for the fixed steady to bear on. Then sort out the hole. May need finger collets in the tailstock and settle for a reamed hole if not enough room, but removing the tailstock might provide enough space for boring?

Alternatively get someone else to do it🙂 or buy a bigger lathe.
21 April 2020 at 23:12 #466208
woody1
Participant
@woody1
Posted by Hopper on 21/04/2020 23:06:09:

You need a cat's cradle. Basically a round sleeve that fits over your square bar where the steady sits. Eight bolts with locknuts – four around the diameter at each end– hold the sleeve in position.

Awesome I new I was over thinking it.

So just use a piece of DOM tube of suitable size drill and tap either side of steady clock in and crack on.

I just spend an hour looking for a "square stock steady"! Cats cradle has thrown up loads! Thanks a million fella!
21 April 2020 at 23:15 #466210
Hopper
Participant
@hopper
Have fun!
21 April 2020 at 23:17 #466211
woody1
Participant
@woody1
Its been a long day grinding valves, I think the compound has got in my veins! I have been think about it all day and how to solve but the bearing in a housing just kept seeming to be the logic. It would work in the same way as a cats cradle but would take a tonne of work, time and a lot swearing to produce.

Again thanks, I can relax now.

Edited By woody1 on 21/04/2020 23:23:04
21 April 2020 at 23:21 #466213
Nigel Graham 2
Participant
@nigelgraham2
One suggestion:

Clean up a section of the bar near the tail end.

Turn a simple cylindrical bush, generously thick-walled, to be a tight push-fit on that area.

You might want to fit a grub-screw that will sink below the outer surface and touch one of the flats (use a shim pad to protect the surface), as the bush contacts the work-piece only on the edges.

Now support the work in the 4-jaw with the steady running on the bush – but ensure accurate centring in the chuck otherwise the outer end of the bar will try to move in a circle exaggerating the error, and cause a lot of problems.

'

Another, based on a long-established trick for good-quality square bar, is to make two such bushes, both a tight push-fit. The first as above, the other split along its length to be gripped wrapped round the stock, in a 3-jaw chuck.

'

Probably the ideal way for a task like that is to use a between-centres boring-bar if you have those and a T-slotted saddle on your lathe. You would still use a long drill for the pilot hole.
21 April 2020 at 23:35 #466216
woody1
Participant
@woody1
Posted by Nigel Graham 2 on 21/04/2020 23:21:58:

One suggestion:

Clean up a section of the bar near the tail end.

Turn a simple cylindrical bush, generously thick-walled, to be a tight push-fit on that area.

You might want to fit a grub-screw that will sink below the outer surface and touch one of the flats (use a shim pad to protect the surface), as the bush contacts the work-piece only on the edges.

Now support the work in the 4-jaw with the steady running on the bush – but ensure accurate centring in the chuck otherwise the outer end of the bar will try to move in a circle exaggerating the error, and cause a lot of problems.

'

Another, based on a long-established trick for good-quality square bar, is to make two such bushes, both a tight push-fit. The first as above, the other split along its length to be gripped wrapped round the stock, in a 3-jaw chuck.

'

Probably the ideal way for a task like that is to use a between-centres boring-bar if you have those and a T-slotted saddle on your lathe. You would still use a long drill for the pilot hole.

Thank you,

Another way to skin a cat! I have made and use a tonne of machined and split DOM tubing to hold work I don't want to mar. This is serious knowledge! So simple when you think about it but hey I'm not ace (yet).

Also how does between centre boring work?

Thanks a million.
21 April 2020 at 23:57 #466217
woody1
Participant
@woody1
Posted by Nigel Graham 2 on 21/04/2020 23:21:58:

One suggestion:

Clean up a section of the bar near the tail end.

Turn a simple cylindrical bush, generously thick-walled, to be a tight push-fit on that area.

You might want to fit a grub-screw that will sink below the outer surface and touch one of the flats (use a shim pad to protect the surface), as the bush contacts the work-piece only on the edges.

Now support the work in the 4-jaw with the steady running on the bush – but ensure accurate centring in the chuck otherwise the outer end of the bar will try to move in a circle exaggerating the error, and cause a lot of problems.

'

Another, based on a long-established trick for good-quality square bar, is to make two such bushes, both a tight push-fit. The first as above, the other split along its length to be gripped wrapped round the stock, in a 3-jaw chuck.

'

Probably the ideal way for a task like that is to use a between-centres boring-bar if you have those and a T-slotted saddle on your lathe. You would still use a long drill for the pilot hole.

I understand mount the work on the T-slotted, boring bar between centres and use the feed. The 7×12's however don't have slots! A major faux paux in my opinion! I dont think a T-slotted is possible for me. Im thinking to buy a spare cross to use and brutalise as a clamping table. There only £30.
22 April 2020 at 03:55 #466227
Paul Lousick
Participant
@paullousick59116
A cat head is sim[le to make. Previous post with an example shown here but instead oh holding in the chuck use a fixed steady. The double row of bolts alows you to centralize it on your job and align it with the axis

Paul

**LINK**

Edited By Paul Lousick on 22/04/2020 03:59:01
22 April 2020 at 08:45 #466248
Ady1
Participant
@ady1
I grabbed a couple of big propshaft bearings and gearbox bearings from a taxi garage years ago

You put the bearing around the workpiece and mount it in the fixed steady

Also handy for supporting very long jobs which need work done at the chuck end

GL

edit: that tubing idea is a great quick fix

Edited By Ady1 on 22/04/2020 08:46:55
22 April 2020 at 08:54 #466251
Clive Brown 1
Participant
@clivebrown1
What size is the 4-jaw?

My 6" 4-jaw is fairly typical for a model-makers lathe. I'd be happy with drilling and boring aluminium alloy as per OP with around 80mm overhang from the chuck jaws without a steady.

Edited By Clive Brown 1 on 22/04/2020 09:09:53
22 April 2020 at 09:35 #466255
Hopper
Participant
@hopper
Lol just reread the OP. Yes its only 100mm long so just hold it in the 4 jaw and drill it.
22 April 2020 at 10:59 #466267
Martin Kyte
Participant
@martinkyte99762
Alternative on a Myford would be mount on the boring table and use a between centres boring bar after drilling.

But as has been said stick it in the 4 Jaw and go without the steady.

regards Martin
22 April 2020 at 12:22 #466286
HOWARDT
Participant
@howardt
I have just bored a 20mm hole in a similar size block of cast iron on my 7×16. Four jaw chuck and light cuts after a 12mm drill, changed boring bar to bigger size as soon as would go in, no steady,
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